Analysis by: Vincent Martin Hermosura
ALIASES:

W32/Sality.AR!tr (Fortinet), Worm.Win32.AutoRun (Ikarus), Virus:Win32/Sality.AN (Microsoft),W32/Pitin.worm (NAI), W32.Pitin.B (Norton), Virus.Win32.Sality.az (v) (Sunbelt), W32/Sality.AC (Antivir), Worm.Generic.376207 (Bitdefender)

 PLATFORM:

Windows 2000, Windows Server 2003, Windows XP (32-bit, 64-bit), Windows Vista (32-bit, 64-bit), Windows 7 (32-bit, 64-bit)

 OVERALL RISK RATING:
 DAMAGE POTENTIAL:
 DISTRIBUTION POTENTIAL:
 REPORTED INFECTION:
 INFORMATION EXPOSURE:

  • Threat Type: Worm

  • Destructiveness: No

  • Encrypted: No

  • In the wild: Yes

  OVERVIEW

Infection Channel: Copies itself in all available logical drives, Downloaded from the Internet, Dropped by other malware

This worm arrives via removable drives. It arrives on a system as a file dropped by other malware or as a file downloaded unknowingly by users when visiting malicious sites.

It drops copies of itself in all removable and physical drives found in the system. It drops an AUTORUN.INF file to automatically execute the copies it drops when a user accesses the drives of an affected system.

  TECHNICAL DETAILS

File Size: 118784 bytes
File Type: EXE
Memory Resident: Yes
Payload: Drops files

Arrival Details

This worm arrives via removable drives.

It arrives on a system as a file dropped by other malware or as a file downloaded unknowingly by users when visiting malicious sites.

Other System Modifications

This worm modifies the following registry entries:

HKEY_LOCAL_MACHINE\SOFTWARE\Windows\
CurrentVersion\Explorer\Advanced\
Folder\Hidden\NOHIDDEN
CheckedValue = "0"

(Note: The default value data of the said registry entry is 2.)

HKEY_LOCAL_MACHINE\SOFTWARE\Windows\
CurrentVersion\Explorer\Advanced\
Folder\Hidden\SHOWALL
CheckedValue = "0"

(Note: The default value data of the said registry entry is 1.)

HKEY_LOCAL_MACHINE\SOFTWARE\Windows\
CurrentVersion\Explorer\Advanced\
Folder\HideFileExt
UncheckedValue = "1"

(Note: The default value data of the said registry entry is 0.)

Propagation

This worm drops copies of itself in all removable and physical drives found in the system.

It drops an AUTORUN.INF file to automatically execute the copies it drops when a user accesses the drives of an affected system.

The said .INF file contains the following strings:

ShellExecute={random file name}
Shell\Auto\Command={random file name}
Shell=Auto

Other Details

This worm requires the following additional components to properly run:

  • {malware path}\thumbs .db

NOTES:

This worm drops copies of itself in all removable and physical drives found in the system using a random file name.

It also modifies the file AUTOEXEC.BAT on the affected system's root folder (usually C:\) by adding the following strings:

  • @Echo Off
  • Echo 81u3f4nt45y - 24.01.2007
  • Echo Don't kill me, i'm just send message from your computer
  • Echo Terima kasih telah menemaniku walaupun hanya sesaat, tapi bagiku sangat berarti
  • Echo Maafkan jika kebahagiaan yang kuminta adalah teman sepanjang hidupku
  • Echo Seharusnya aku mengerti bahwa keberadaanku bukanlah disisimu, hanyalah lamunan dalam sesal
  • Echo Untuk kekasih yang tak kan pernah kumiliki 3r1k1m0
  • pause

To properly perform its routines, this worm needs its DLL component, thumbs .db, in the malware's execution folder. It then creates a copy of the said DLL components in the Windows folder using the file name, thumbs .db. The said file is also detected as WORM_VB.DTH.

  SOLUTION

Minimum Scan Engine: 9.700

Step 1

Note that not all files, folders, and registry keys and entries are installed on your computer during this malware's/spyware's/grayware's execution. This may be due to incomplete installation or other operating system conditions. If you do not find the same files/folders/registry information, please proceed to the next step.

Step 2

Before doing any scans, Windows XP, Windows Vista, and Windows 7 users must disable System Restore to allow full scanning of their computers.

Step 3

Scan your computer with your Trend Micro product and note files detected as WORM_VB.DTH

Step 4

Restart in Safe Mode

[ Learn More ]

Step 5

Restore this modified registry value

[ Learn More ]

Important: Editing the Windows Registry incorrectly can lead to irreversible system malfunction. Please do this step only if you know how or you can ask assistance from your system administrator. Else, check this Microsoft article first before modifying your computer's registry.

  • In HKEY_LOCAL_MACHINE\SOFTWARE\Windows\CurrentVersion\Explorer\Advanced\Folder\Hidden\NOHIDDEN
    • From: CheckedValue = "0"
      To: CheckedValue = "2"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Windows\CurrentVersion\Explorer\Advanced\Folder\Hidden\SHOWALL
    • From: CheckedValue = "0"
      To: CheckedValue = "1"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Windows\CurrentVersion\Explorer\Advanced\Folder\HideFileExt
    • From: UncheckedValue = "1"
      To: UncheckedValue = "0"

Step 6

Search and delete AUTORUN.INF files created by WORM_VB.DTH that contain these strings

[ Learn More ]
ShellExecute={random file name} 
Shell\Auto\Command={random file name}
Shell=Auto

Step 7

Restart in normal mode and scan your computer with your Trend Micro product for files detected as WORM_VB.DTH. If the detected files have already been cleaned, deleted, or quarantined by your Trend Micro product, no further step is required. You may opt to simply delete the quarantined files. Please check this Knowledge Base page for more information.

Step 8

The following created files/folders/registry keys/registry entries cannot be identified by the user since there are no reference values in the created key. The only way it can be identified is by comparing the present system information with a backup. Note that the said components do not have to be deleted since it won't be harmful to the system.

  • {random file name} which is a copy of itself in physical and removable drives.


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